Transport analysis of stellarator reactors

The performance of deuterium-tritium stellarator reactors is studied with a new, fast, onedimensional (1-D) transport survey code that is based on the spectral collocation method. Two operating modes with different signs of the assumed radial electric field are identified. The operating mode with a positive electric field is characterized by high temperatures and moderate densities, whereas the other mode has lower temperatures and higher densities. Both modes can be applied in possible reactors that can tolerate a large alpha particle energy loss. The sensitivity to device parameters and profile assumptions is examined. Scaling expressions useful for parametric studies are obtained for different quantities of interest, and the 1-D code results are compared with results derived from an empirical scaling relation. Deuterium-helium-3 operation is also feasible but is more demanding. The implications for stellarator reactor design optimization are discussed.